The present invention relates to an electronic valve control apparatus, and more particularly relates to control apparatuses that are used to control a plurality of electromotive or electromagnetic valve devices which are respectively installed at considerable distances from a power source for driving the valve devices.
To date, large scale sprinkler irrigation systems for spraying water over the fields have been employed mainly for plantations, orchards, golf links and the like. Such irrigation systems provide water supply pipelines for supplying irrigation water or desired liquid solutions containing insecticide or fertilizer under pressure to affect plant or lawn growth. The water or solution is distributed by operation of valve devices that are mounted to the pipelines for fluid flow control.
Generally such sprinkler irrigation systems consist of a central remote control station and long electric power supply lines connecting the control station to electromotive or electromagnetic valve devices which are arranged in the water supply pipelines.
Regulation of the valve devices is done through the remote control in response to the predetermined sprinkler time schedules respectively preset in the control system by way of the electric power supply lines.
As a prior sprinkler irrigation system, Kah, Jr. U.S. Pat. No. 3,747,620 teaches a line pressure variation control system, which requires, in the case of control for large numbers of valves provided therein, a plurality of pumps mounted to various sites beside the pipeline. In addition, electric power supply lines for the driving of the pumps and the monitoring of the water pressure distribution in the pipeline network are required.
Milovancevic U.S. Pat. No. 3,777,976 discloses electronically controlled watering system providing a solid state electronic control system therein with a programing function. This system employs an external electric power source with an electric power supply line for valve operation.
The conventional valve control system with a remote control station requires, as above described, long power supply lines connecting the remote control station with electromotive or electromagnetic valve devices.
Therefore, it has several disadvantages including those of high initial capital cost and possible damage by lightening.